Simplify away futility pruning for captures

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 4650b1579bf0e11dafd78722151ab5d54f0370d5..eaa79fb92bffe836472c6382d63daac2f10aa7ab 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -192,7 +192,7 @@ namespace {
 void Search::init() {
 
   for (int i = 1; i < MAX_MOVES; ++i)
-      Reductions[i] = int((22.0 + 2 * std::log(Threads.size())) * std::log(i));
+      Reductions[i] = int((22.0 + 2 * std::log(Threads.size())) * std::log(i + 0.25 * std::log(i)));
 }
 
 
@@ -829,7 +829,7 @@ namespace {
         assert(eval - beta >= 0);
 
         // Null move dynamic reduction based on depth and value
-        Depth R = (817 + 71 * depth) / 213 + std::min(int(eval - beta) / 192, 3);
+        Depth R = (982 + 85 * depth) / 256 + std::min(int(eval - beta) / 192, 3);
 
         ss->currentMove = MOVE_NULL;
         ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];
@@ -1049,15 +1049,6 @@ moves_loop: // When in check, search starts from here
                   && captureHistory[movedPiece][to_sq(move)][type_of(pos.piece_on(to_sq(move)))] < 0)
                   continue;
 
-              // Futility pruning for captures
-              if (   !givesCheck
-                  && lmrDepth < 6
-                  && !(PvNode && abs(bestValue) < 2)
-                  && !ss->inCheck
-                  && ss->staticEval + 169 + 244 * lmrDepth
-                     + PieceValue[MG][type_of(pos.piece_on(to_sq(move)))] <= alpha)
-                  continue;
-
               // See based pruning
               if (!pos.see_ge(move, Value(-221) * depth)) // (~25 Elo)
                   continue;